Building session at the 2007 Fest?

I am very interested. Had a discussion with Squid, and he seemed pretty excited about it. If it can be done on a real poor mans budget that has more time and interest than dollars, and you guys are willing to share you're knowledge, I don't see how it could be anything but a successs. Even people that can't or don't wan't to spend the money right away can get a real "inside view" of what's required to go from 0 to 100. :thmbsp:

Hey-Hey!!!,
Well then, seems that the next thing is to come to some consensus on the circuit design. The E-Linear circuit Pete laid out has some values laid out that may not apply to other variants. From the D3a and its g2 regulated voltage, to the PS design, it has been tuned for that circuit.

The power tube can also be run full-pentode, and still run the driver from the screen tap. It's just a question of load-line calculation, and driving it where it's at its best. It can run 6L6's, or EL34's or 6550's( or EL84, 6V6, 7591A, EL500 and a host of TV sweeps ). An interesting option for me would be the TV sweeps run as pentodes at moderate voltage and reasonable load. There are a few neat ones that would offer reasonable power, and cost $5-10 each.

Also it's a bit much for a weekend build. Stuff like a dropping resistor and bypass cap to the driver pentode will be both cheaper and simpler.

Remember, it's your amp. I'll be able to assist the design process, and make sugestions on the circuit. Once we've got that part down into something that looks buildable, we'll move on to parts sourcing and layout.
cheers,
Douglas

Hey-Hey!!!,
ANybody interested in building should drop me an email. I'll run a 'reply-all' mailing as we discuss the project. Those of you in SE Michigan( or withing your sane driving distance ), are welcome to visit in person to smoke-test, or troubleshoot as the project gets built. I'll be building either way....

Or open a thread in DIY.... if the interest is there, I'll be there to make it happen.

Maybe it will even appear as a low liability thing, and a Fest Build could still happen.
Cheers.
Douglas
Pentode-at-netscape-dot-com

Now that is both interesting and useful. Say for example, taking a single triode gain stage, and examining the effects of load changes, and operating points with a signal generator and distortion analyzer. Pick a triode---any triode---and examine how to use it in circuit.

This sort of measurement would be interesting to me. If one could look up the answers, there's be no reason to actually do it...of course, engaging in experiments, in front of students, real-time, and w/o a lot of previous confirmation of the results is one slightly risky business....

Hey Douglas I was thinking something along the lines of what Luvvinvinyl had to say.

As I'll have a room next year so time will be limited plus the amount of stuff to see at
the show, a building project would severely cut into the other enjoyments of the fest.

So I was thinking once a final build is determined we build it on AK/here local and show
what we've created at next years fest and have them looked over by the guru's like
yourself and others that would help to see how we did or tweak or whatever.

That way even people who can't make it to the fest could tag along with the project
and even jump in from afar with building one themselves then see what happens with
the ones built and brought to the fest.

I would jump in on this build in a form like mentioned above and would travel local to
get guidance or help in any way I could. But to really think about my next years fest
I have to be honest and would not have the time for a build at the fest.

What yu think? Also you to Tubino as I know you have extensive knowledge in this area
also and could/would maybe be able to meet somewhat locally on a get together?

Hey-Hey!!!,
I would be the greatest loser of time at the '07 Fest if the build project had gone ahead. I realized that from the start. Having it cancelled ahead of time is somewhat of a relief...

Anyway, like I offered, I'll put up what ever effort needs to be made to present a group build project. Tubino likes SE, and we have already found one that has his interest. My wife's 6V6 monoblock project is another simple one. That one does take a special OPTx, but getting Heyboer to clone the little Chicago would not be a great issue...I want a slilght modification to it anyway, so a takedown is in the cycle plan for that one anyway.

We've got about a year to get a simple project up and running so a finished/tweaked amp can be brought to the Fest. Just need to get moving...

I suggested a small mail-list for discussion, similar to how Jeff's Audio group is run. That 'Reply-All' is a powerful thing, and I can't think of a better way to do it. Aside from creating the original mailing, and adding new folks, it's a self-powered discussion as far as I see it.

I like to see the DIY craft spread, and I'll make the effort to do it. This project is just small way I can pay forward the folks who taught me.
cheers,
Douglas

OK so it sounds like your in the same boat and a build at the fest would take up much of
our fest experience, (I agree YOU would be severely limited on time) so doing a build here
or through email/local is the thing to try and acomplish by next festifus and somewhat of
the preferred way of doing it!

Sounds good to me.

I have a set of fisher output's plus power from a 7591 amp and a set from a 7868 both
are integrated's that I could use the iron from and build whatever is suggested or go in
on something a group was to decide on, I'm flexable and either works for me.

I haven't done a build yet, just mods and upgrades so any build would be good from my
point of you and could definatly use the experience. I'm in for whatever is being done!

My wife's 6V6 monoblock project is another simple one. That one does take a special OPTx, but getting Heyboer to clone the little Chicago would not be a great issue...I want a slilght modification to it anyway, so a takedown is in the cycle plan for that one anyway.

Click to expand...

Which little Chicago OPT is that? I was given a pair of cute little Chicago OPTs years ago, and when I did a cliplead trial of several different OPTs in a 1626 amp I built, the little Chicagos were my favorites. I forget the model number though...

It can run 6L6's, or EL34's or 6550's( or EL84, 6V6, 7591A, EL500 and a host of TV sweeps ). An interesting option for me would be the TV sweeps run as pentodes at moderate voltage and reasonable load. There are a few neat ones that would offer reasonable power, and cost $5-10 each.

Click to expand...

I'm very much attracted by using non-trendy tubes like sweep tubes. IIRC, there are some different limits that must be observed (much lower screen voltage?), but that's do-able. My very first scavenged tube amps were a pair of DuKane PA amps using 6CD6 tubes, an odd 2.5A filament tube that I think was used in some McIntosh amp too... Hate to sound like a broken record, but there are a lot of sweep tubes I could donate for a project. The big 'uns like EL-509 are kinda on the pricey side, but there are many little cousins -- and if you don't like the price, just design around the weirdo fil voltage variations! Plenty of 26 and 42 volt cheapies out there. Or in my storage unit.

OK so it sounds like your in the same boat and a build at the fest would take up much of
our fest experience, (I agree YOU would be severely limited on time) so doing a build here
or through email/local is the thing to try and acomplish by next festifus and somewhat of
the preferred way of doing it!

Sounds good to me.

Click to expand...

Sounds good to me too. If you guys are thinking of a local or email kind of thing, count me in! I just plain ran out time at the fest, but it could be fun to get together on a Saturday or something.